1. Field of the Invention
The present invention relates to an electron-emitting device, an electron source having the electron emitting device, and an image-forming apparatus for using and applying the electron source, and to a display apparatus for broadcast on television, a display apparatus for a TV conference system, a computer, and so on, and an image-forming apparatus used as an optical printer, which is composed of a photosensitive drum and the like. The present invention further relates to a method for manufacturing an electron-emitting device.
2. Related Background Art
Development of an image-forming apparatus using an electron-emitting device has been pursued in recent years.
A field emission (FE type) electron-emitting device has become a focus of attention as one of cold electron sources. The field emission electron-emitting device applies a strong electric field of 106 V/cm or more on metal and emits an electron from a metal surface.
If a cold electron source of FE type is put into practical use, a low-profile emissive type image display apparatus can be achieved, thereby saving power consumption with light weight.
As an example of an vertical type FE, FIG. 13 shows an emitter 135 formed into a circular cone or a quadrangular pyramid in substantially a perpendicular direction from a substrate 131. For example, an vertical type FE has been known, which is (hereinafter, referred to as a “spindt type”) in C. A. Spindt, “Physical Properties of thin-film field emission cathodes with molybdenum cones”, J. Appl. Phys., 47, 5248 (1967) and so on.
Meanwhile, FIG. 14 shows the configuration of a lateral type FE. Besides, in FIG. 14, reference numeral 141 denotes a substrate, reference numeral 142 denotes an emitter electrode, reference numeral 143 denotes an insulating layer, reference numeral 145 denotes an emitter, reference numeral 146 denotes an anode, and reference numeral 147 denotes the shape of an electron beam emitted to the anode. The emitter 145 having a pointed end and a gate electrode 144 are disposed in parallel on the substrate, and a collector (anode electrode) is formed above the substrate having the gate electrode and the emitter electrode thereon (refer to U.S. Pat. No. 4,728,851, U.S. Pat. No. 4,904,895 and the like).
Further, as an example of an electron-emitting device using fibrous carbon, Japanese Patent Application Laid-Open No. 8-115652 discloses the configuration in which thermal decomposition is performed on a fine catalyst metal by using an organic compound gas to deposit fibrous carbon in a fine gap.
As a conductive layer for a carbon nanotube, Japanese Patent Application Laid-Open No. 11-194134 and EP0913508A2 disclose a metal layer made of titanium (Ti), zirconium (Zr), niobium (Nb), tantalum (Ta), molybdenum (Mo). Moreover, Japanese Patent Application Laid-Open No. 11-139815 discloses that Si is used as a conductive substrate.
In a conventional image-forming apparatus using an FE electron source, an electron beam spot (hereinafter, referred to as a beam diameter) is obtained according to a distance H between an electron source and phosphor and a driving voltage Vf of an anode voltage Va and an element. The beam diameter is about a submillimeter and its resolution has been sufficient for an image-forming apparatus.
However, as for an image-forming apparatus, a higher resolution has been demanded in recent years.
Furthermore, as the number of display pixels increases, power consumption rises due to a device capacity of an electron-emitting device when driving. Thus, a reduced device capacity, a reduced driving voltage, and an increased electron emission efficiency of an electron-emitting device have been demanded.